| University of Windsor |
School of Physical Sciences
Chemistry & Biochemistry
PhD - 1990 University of Alberta
NSERC, Postdoc 1991-1993 Oxford/Caltech
Research Associate 1994 University of Alberta
Research Associate 1994-1996 - MIT
Lecturer 1997 University of Sussex
Associate Professor 1998 University of Windsor
The fabrication of shape, porosity, and electronic properties of nanoscale materials is one of the frontiers of modern science. Since the discovery of periodic mesoporous materials in 1992, a wide variety of new materials have been synthesized that exploit the ability of these nanostructured substrates to act as hosts for a broad range of inorganic and organic guest species which are too large to be included in the smaller pores of microporous zeolites.2 The discovery of stable mesoporous transition metal oxides in 19963 further expands the potential range for host-guest inclusion reactions. Although very little is known about the properties of these materials, recent work in the applicant's group has shown that the inorganic framework of mesoporous niobium oxide acts as an electron acceptor, making it the first reducible molecular sieve.4 This property is due to the capacity for variable oxidation states in the walls of the inorganic host and allows the individual mesotubes to act as charge-balancing sheaths for non-stoichiometric grains of the type Mn+/M(n+1)+ residing in the pores.5
Recently we showed that mesoporous niobium oxide can act as a host for conducting mixed oxidation state one-dimensional nanowires of bis-benzene chromium,6 normally an insulator. This is because the oxidizing ability of the mesostructure can be used to introduce charge-carrying holes in the conduction band of the organometallic phase. In order to more fully understand this system we intend to do a systematic survey of the effect of bis-arene and metallocene reduction potential, electronic configuration, and loading level on the magnetic and electronic properties of these composites. The novelty of this work is that it allows us to tune the electron density in the conduction band in the encapsulated molecular wire. We have already synthesized materials with (C5H5)2Ni, (C6H6)2M (M = Cr, V), (C6H4Me)2Ti, and (1,3,5-tri-tert-butylbenzene)2Y in the pores of the mesoporous niobium oxide and the properties of these materials are currently under investigation.
Of special interest to us is the intercalation of superconducting materials into the mesostructured niobium oxide framework, since many materials of this type posses unit cells much larger than the pore dimensions of zeolites. Since dramatic changes in electronic and magnetic properties occur as the grain size of a material approaches the nanometer dimension, we anticipated that the quantum confinement of a superconductor in a mesostructured host may lead to unusual properties not observed in the bulk state. Because of its small unit cell size (14-15 Å) and solubility in organic solvents, we chose to investigate the intercalation of K3C60 into mesoporous niobium oxide materials with pore sizes in the 20 Å range. In previous studies the three-minus state was found to be the only phase that has superconducting properties. The reason for this is not fully understood as some calculations have suggested that this state should be insulating and that the unique properties are in fact due to elusive materials with oxidation states fractionally above or below the three-minus state. The advantage of this system over the bulk state is that the walls of the material can oxidize the fulleride to a lower state and that once inside the pores, the oxidation state of the fullerene can further be adjusted by further addition of potassium naphthalene. Our first results7 have demonstrated that the three-minus state is insulating, providing the first experimental evidence backing up the calculations that K3C60 should be an insulator. We plan to pursue comprehensive studies on the electronic and metallic properties of the mesoporous oxide fullerene intercalates with the view in mind of determining the optimal oxidation state of the fullerene for metallic behavior and the minimum pore size necessary to deliver the onset of superconducting behavior (i.e., by increasing the pore size, more repeat units of the fullerene can be included in the intercalate and the material will more closely resemble the bulk state.
RECENT PUBLICATIONS:
1. Ye, B., Trudeau, M. and Antonelli, D. M. "Observation of a Double Conductivity Maximum and the Role of Oxidation State in Metallic Potassium Fulleride Nanowires Supported by a Mesoporous Niobium Oxide Host Lattice" submitted to Nature.
2. He, X., Trudeau, M. and Antonelli, D. M. "One Dimensional Bis-Benzene Vanadium Mesoporous Niobium Oxide Composites: the Effect of Electron Configuration on Conductivity" submitted to Chemistry of Materials.
3. Murray, S., Trudeau, M. and Antonelli, D. M. "XPS and Magnetic Studies on the Effect or Pore Size, Wall Thickness, and Composition on Superparamagnetic Cobaltocene-Mesoporous Nb, Ta, and Ti Oxide Composites" Inorganic Chemistry, in press.
4. Vettraino, M., Trudeau, M. and Antonelli, D. M. "Conductivity and XPS studies of Electroactive Alkali Metal-Doped Mesoporous Nb, Ta, and Ti Oxides" submitted to Chemistry of Materials.
5. Ye, B., Trudeau, M. and Antonelli, D. M. "Synthesis and electronic properties of potassium fulleride nanowires in a mesoporous niobium oxide host" Advanced Materials, in press.
6. Murray, S., Trudeau, M. Antonelli, D. M. "Synthesis and Magnetic Tuning in Superparamagnetic Cobaltocene-Mesoporous Niobium Oxide Composites" Advanced Materials, 2000, 12, 1339.
7. He, X., Trudeau, M. and Antonelli, D. M. "Electronic Properties of Novel Mixed Oxidation State Bis-Arene Chromium Nanowires Supported by a Mesoporous Niobium Oxide Host" Advanced Materials, 2000, 12, 1036.
8. Vettraino, M., Trudeau, M. and Antonelli, D. M. "Synthesis and Electronic Properties of Reduced Mesoporous Sodium Niobium Oxides" Advanced Materials, 2000, 12, 337.
9. Antonelli, D. M. and Trudeau, M. "SEM and TEM Investigations of Macroporous and Toroidal Mesostructured Transition Metal Oxides" Studies in Surface Science and Catalysis, vol. 129 Sayari, A., and Pinnavaia, T. J., ed. Elsevier, Amsterdam, 2000.
10. Antonelli, D. M. "Synthesis and Mechanistic Studies of Sulfated Meso- and Microporous Zirconias with Chelating Carboxylate Surfactants," Advanced Materials, 1999, 11, 488-492.
11. Trudeau, M. and Antonelli, D. M. "Dynamic Behavior and Mesoscopic Phase Changes in Conducting Toroidal Macro- Mesoporous Mixed Valent Molybdenum Oxides," Angewandte Chemie-International Edition in English, 1999, 38, 1471-1475.
12. Antonelli, D. M. "Synthesis of Highly Ordered Macro- Mesoporous Niobium Oxide Molecular Sieves," Microporous and Mesoporous Materials, 1999, 33, 209-214.
13. Antonelli, D. M. "Hollow Ordered Zirconia Microcage Formation by Spherical Micelle Templating with Chelating Triol Surfactants," Microporous and Mesoporous Materials, 1999, 28, 505-510.
14. Antonelli, D. M. "Synthesis of Phosphorous-Free Mesoporous Titania via Templating with Amine Surfactants," Microporous and Mesoporous Materials, 1999, 30, 315-319.
15. Bell, T. and Antonelli, D. M. "Synthesis of Mesostructured Platinum-based Materials through Thermal Decomposition of Self-assembled Metal Carbonyl-surfactant Phases" Advanced Materials, 1998, 10, 846.
16. Blake, R. E., Antonelli, D. M., Henling, L. M., Schaefer, W. P., Hardcastle, K. I. and Bercaw, J. E. "A Cationic Imido Complex of Permethyltantalocene: H2 and Carbon-Hydrogen Bond Activation, [2 + 2] Cycloaddition Reactions, and an Unusual Reaction with Carbon Dioxide That Affords Coordinated Isocyanate" Organometallics, 1998, 17, 718.
17. Antonelli, D. M., Leins, A. and Stryker, J. M. "Ethylene Polymerization with Half-Sandwich Allyl Imido Complexes of Tantalum" Organometallics, 1997, 16, 2500.
18. Antonelli, D. M., Gomez, P., Mountford, P. Martins, Ana M. and Green, M. L. H. "Reactivity of h -Cyclopentadiene-4-Imidopropylniobium Derivitives [Nb(h -s -C5H4(CH2)3N)Cl2] and [Nb(h -s -C5H4(CH2)3N)Me2]" Journal of the Chemical Society, Dalton Transactions, 1997, 2435.
19. Wong, M. S., Antonelli, D. M. and Ying, J. Y. "Synthesis and Characterisation of Phosphated Mesoporous Zirconium Oxide" Nanostructured Materials, 1997, 9, 165.
20. Antonelli, D. M. and Ying, J. Y. "Mesoporous Materials" Current Opinion in Colloid & Interface Science, 1996, 1, 523-529.
21. Antonelli, D. M. and Ying, J. Y. "Synthesis of a Stable Hexagonally Packed Mesoporous Niobium Oxide Molecular-Seive Through a Novel Ligand-Assisted Templating Mechanism" Angewandte Chemie-International Edition in English, 1996, 35, 426-430.
22. Antonelli, D. M., Nakahira, A. and Ying, J. Y. "Ligand-Assisted Liquid-Crystal Templating in Mesoporous Niobium Oxide Molecular Sieves" Inorganic Chemistry, 1996, 35, 3126- 3136.
23. Antonelli, D. M. and Ying, J. Y. "Synthesis and Characterisation of Hexagonally Packed Mesoporous Tantalum Oxide Molecular-Sieves" Chemistry of Materials, 1996, 8, 874-881.
24. Antonelli, D. M. and Ying, J. Y. "Synthesis of Hexagonally Packed Mesoporous TiO2 by a Modified Sol Gel Method" Angewandte Chemie-International Edition in English, 1995, 34, 2014-2017.
25. Antonelli, D. M., Tjaden, E. B. and Stryker, J. M. "A thermally Stable Carbonyl Complex of Zirconium (IV) Structure and Reactivity Ramifications of Strong s ® p * Electron Donation" Organometallics, 1994, 13, 763-765.
26. Antonelli, D. M., Schaefer, W. P., Parkin, G. and Bercaw, J. E. "Synthesis and Characterisation of (h 5 C5Me5)2TaCl(THF), a Useful Synthetic Precursor for the Preparation of Oxo, Imido, and Methylidene Derivitives of Permethyltantalocene" Journal of Organometallic Chemistry, 1993, 462, 213-222.
27. Antonelli, D. M., Mountford, P. and Green, M. L. H. "Synthesis of h -Cyclopentadiene-4- Imidopropylniobium Derivitives [Nb(h -s -C5H4(CH2)3N)Cl2] and [Nb(h -s - C5H4(CH2)3N)(PMe3)Cl2]" Journal of Organometallic Chemistry, 1992, 438, C 4-C8.
28. Antonelli, D. M. and Cowie, M. "Unusual, Coordinatively Unsaturated Rhodium Rhenium and Iridium Rhenium Alkyl, Acyl, and Hydrido Complexes - Structure of [RhRe(CH3)(CO)4(Ph2PCH2PPh2)2][CF3SO3].3CH2Cl2" Organometallics, 1991, 10, 2550- 2559.
29. Antonelli, D. M. and Cowie, M. "Unusual Mixed-Metal Carbonate-Bridged Complexes Via Oxidation of a Carbonyl Ligand in [RhM(CO)4(Ph2PCH2PPh2)2] (M = Mn, Re) and [IrRe(CO)5(Ph2PCH2PPh2)2]" Organometallics, 1991, 10, 2173-2177.
30. Antonelli, D. M. and Cowie, M. "Oxidative-Addition Reactions Involving the Mixed-Valence Complex [RhRe(CO)4(Ph2PCH2PPh2)2] - Influence of the Coordinatively Unsaturated Rh (+1) Center of the Saturated Re (-1) Center" Inorganic Chemistry, 1990, 29, 4039-4045.
31. Antonelli, D. M. and Cowie, M. "Ascertaining the Roles of Each Metal in the Activation of S- H Bonds in Hydrogen-Sulfide and Thiols by the Heterobinuclear Complex [RhRe(CO)4(Ph2PCH2PPh2)2]" Inorganic Chemistry, 1990, 29, 3339-3345.
32. Antonelli, D. M. and Cowie, M. "A convenient General-Route to a Series of Diphosphine- Bridged Heterobinuclear Complexes thet Contain Rhodium and Structures of the Mixed-Valent Complexes [RhMn(CO)4(Ph2PCH2PPh2)2] and [RhRe(CO)4(Ph2PCH2PPh2)2]" Organometallics, 1990, 9, 1818-1826.
commercially available mesoporous materials
If you have comments or suggestions, please e-mail me at danton@uwindsor.ca